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k_gwie 11-17-2012 05:58 PM

furnace fan for not being able to stop automatically
4 Attachment(s)
I have a problem with furnace fan for not being able to stop automatically.
My guest would be Fan & limit control. I have no luck finding it and somebody said the furnace is too old. Could someone kindly find a replacement w/modification for me or similar one? Thanks in advance, Gwie

Here is the info: GE 21LG(gas fired warm air furnace) Serial no: 23265519
Fan & limit control cat: 5733090AF 115V 1/2HP

carmon 11-17-2012 06:13 PM

wow...... i would suggest a new furnace......... that one is ancient and in efficient..... may not be an option for you but those are my thoughts....

how 11-17-2012 06:29 PM

Here on the West Coast of surviving furnace dinasaurs, I only have 3 customers left with those GE units.
The difficulty in replacing the fan/limit control is the short depth that is allowed for a probe. Look for the shortest one you can find. There are ways to box them away from the furnace body but my advise as a lover of older furnaces is..
Change the furnace. Just about every other part on that furnace is OBS, equally difficult to replace and likely to leave you with extended downtimes.

Chimmy 11-17-2012 09:42 PM

You can simply run the fan by time delay
rather than the limit/temp delay combo.
You can get a limit to fit there , I would use the 3 wire limit and use the electric heat option for fan control in heat mode available on most stats and use the time delay on the make and break, the 3 wire limit I like as if the limit opens the 3rd terminal sends the24v power to the fan relay to keep the fan running as the old limit would have done.

Chimmy 11-17-2012 09:47 PM

Whatever you do DONT toss it out!
I think those old GE units are bullet proof as evidenced by its continued operation 40+ yrs later! The heat exchanger on that is about 100lbs of iron!
The clamshell exchangers they make now you can dent with a punch!
and they are so circuitous they require the draft to be induced and the rest of the fragile expensive (if having it fixed by a pro) components that make the 80% of yesterday the 90% of today.
Many units are tossed in using the old ductwork which is no benefit to you as the eficiency gained is lost by the ductworks sizing and lack of R value, not to mention sags and leaks.

beenthere 11-18-2012 05:11 AM

gwie, see if you have clearance to use a 3" insert. If so, then a Camstat FAL3 C05TD-120-A should work for you.

k_gwie 11-18-2012 07:40 AM

Thanks for all the reply - Actually the dept is 1.75" and I found below(please let me know if this is possible and easy to do the wiring - the existing one has 4 wires):

Part #: L4064D1002
Category: Gas Furnace:Controls
Vendor: Honeywell Price: USD $ 159.00

  • High Limit Temperature Range (F) 100 F to 250 F
  • Element Insertion Length (in.)1 1/2 in.
  • Fan-on Range (F) 125 F
  • Fan-off Range (F) 100 F
  • Approvals CSA Certified
  • High Limit Temperature Range (C) 38 C to 121 C
  • Electrical Rating Fan (AFL) 7A @ 240 Vac/14A @ 120 Vac

beenthere 11-18-2012 07:46 AM

That will work.

You have to remove/break the jumper at the bottom 2 terminals for a wire connection like you have. Its a very easy control to install.

k_gwie 11-22-2012 07:02 PM

1 Attachment(s)
I just bought the FAN & LIMIT and I LABELED them. Please let me know how to do the wiring. Like you said before, No 5 is the jumper that has to be broken. How about no 1 and 2, 3 and 4, and also, dial setting wheel? Thanks again

beenthere 11-22-2012 08:46 PM

On your old control. Trace out the wire that goes to the fan. The wire that goes to the fan, the wire on the opposite side of the case should be the wire that feed voltage to the control. I believe on yours it the wires on the right in the photo.
They will go to 1 and 2 of the new fan limit. The other 2 wires then will go to 3 and 4.

Fan off 110, fan only 140, limit can be left at 200.

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